The invention relates to a component with rectifying function using ion charge transport. More particularly the invention relates to rectifiers for particles which use especially thin layers in solids or thin membranes.
It is known as state of the art to form rectifiers for electrons on a semiconductor basis. They are well known and described in textbooks in semiconductor physics and semiconductor technology. In the technical literature in the last years, proposals have been made for rectifiers for ions which are analogous to the rectifiers for electrons on a semiconductor basis. In laboratory tests, the rectifying effect can be detected.
It is an object of the invention to provide a component with a rectifier function using ion charge transport with which can achieve the ion transport in other ways than are known in the art.
These objects are achieved with a component with a rectifier function with the aid of ion charge transport which has a layer stack of a multiplicity of layers which follow one another and form an asymmetrical course of the energy level and wherein an electric field is applied to this stack.
The following should be noted:
The component according to the invention with this rectifier function rests on other principles than those described as known above for rectifiers for ions. The basis of the component of the invention forms an exact theory of nonlinear mobility of particles in potentials without inversion symmetry. The component of the invention, however, can be described without this mathematical description.
The mobility of the ions/particles based upon atomic hop processes from one potential minimum to another potential minimum is involved. The potential for particles can have the shape of a staircase, whereby from the last step there is a sharp drop to the starting level. The mobility of particles in the hop process under the influence of a force is the same in both directions for small forces. This corresponds to the ohmic case in electrical transport. For very strong forces in one direction, the mobility due to the inverse of the mean of the inverse jump rate determines the corresponding direction. The means of the inverse jump rate all of which are the same (xe2x80x9cupward staircasexe2x80x9d) is much smaller than the means of the inverses of a very small and multiple size jump rate (each staircase). As a consequence the mobility as inverses of both of these means has a large step up and under a strong force and is small in the downward stepping direction. The here given clarification depends upon one dimensional potential which can possibly be realizable even in channels in membranes. They can however transition to three-dimensional layer structures when the layers are uniform in directions perpendicular to the movement direction.
It has been found to be advantageous to form the component according to the invention as a stack of multiple layers which collectively and one after the other contribute an asymmetric course to the energy level and also in which an electric field is applied to this layer stack.
Advantageously, a multiplicity of successive layer stacks is provided.
In an especially advantageous manner, one or more layers of the layer stack, especially all layers are constructed from a monolayer.
In another feature of the invention the component of the invention is configured highly advantageously with an asymmetric energy level course so that in the successive layers, each layer has an energy level which does not fall below the energy level of the preceding layer and so that the energy level from layer to layer increases in value. In this manner, a rectifying function is positively influenced.
The component of the invention for formation of the layer stack, can be made of semiconductive material. It is, however, foreseeable to provide another material for formation of the layer stack or its layers.
The above depicted potentials according to the invention are realized by the application of monoatomic layers of different atom types. Advantageously or preferably one can select the materials for optimization of selected boundary conditions as a function of the potential structures of certain materials. Another advantageous embodiment of the components according to the invention involves the formation of channels in selected membranes.
The component according to the invention with the proposed rectifier function can be used in the field of sensor technology. In this case, certain particles are driven through a barrier layer which cannot be overcome in the reverse direction by them. Advantageously with the components of the present invention, switching effects are obtained by a change in time of the forces. In dependence upon the formation of the layer structure with corresponding lateral extents, it can be advantageous to also transport large quantities of ions/particles.
The rectifying effect for particles, especially ions, obtained in accordance with the invention in layer structures or membranes is based upon the exploitation on non-inversion-symmetrical potential courses as well as the use of relatively strong forces upon the particles such that one operates in the non-linear ranges of the mobility of the particles, especially ions.
Uniform layer structures can be produced, for example, by means of molecular beam epitaxy (MBE) techniques.